The invention relates to an apparatus and method for adjusting the position of a lens array in a motion sensor module. More particularly, the lens array has a series of ribs, or teeth, which engage with a lens adjuster to maintain a desired position. The lens adjuster can be a single tooth or a pawl for engaging with the lens array ribs. A user can slide the lens array to a desired focal point location, and the lens adjuster will maintain the lens array position. Alternatively, the lens adjuster can be a pinion, interacting with ribs forming a rack on the lens array for vernier adjustments.
A need exists to adjust the position of a lens array in a sensor module to eliminate blind spots in the coverage pattern of the sensor module. The coverage pattern of the sensor module determines the zone of coverage, or field of view, of the sensor.
Passive infrared sensors are commonly used in motion detectors to determine the presence or absence of individuals, generally determining if someone enters a zone of coverage. These detectors can be connected to security systems alerting others of an intrusion into the zone of coverage. These detectors can also be connected to light switches for turning lights on when a person is present in the zone of coverage, or deactivate the lights when a person is no longer present in the zone of coverage.
These motion detectors generally have a passive infrared sensor attached to a printed circuit board contained in a housing. A lens array is positioned in front of the sensor, and focuses the infrared profile of a person or object as it moves across the zone of coverage. The position of the sensor relative to the focal point of the lens array determines the coverage pattern of the sensor. The lens array is generally held in a predetermined position by a lens retainer. However, tolerance buildup during manufacture can alter the predetermined lens position. Consequently, there is a need for a lens adjuster for positioning the lens to eliminate blind spots in the sensor module coverage pattern.
Some examples of passive infrared motion detectors are U.S. Pat. No. 5,764,146 to Baldwin et al.; U.S. Pat. No. 4,672,206 to Suzuki et al.; U.S. Pat. No. 5,442,178 to Baldwin; U.S. Pat. No. 5,772,326 to Batko et al.; U.S. Pat. No. 5,790,040 to Kreier et al.; and U.S. Pat. No. 5,026,990 to Marman et al.; and are incorporated herein by reference.
Accordingly, it is a primary object of the invention to provide an adjustable lens array for use in a motion sensor module.
Another object of the invention is to provide a user adjustable lens adjuster for altering and maintaining the position of a lens array in a motion sensor module.
Another object of the present invention is to provide a user adjustable lens adjuster for retaining a lens array and altering the position of the lens array relative to a sensor.
Yet another objective of the present invention is to provide a user adjustable lens adjuster and a lens array such that the lens array can be repositioned independently along a linear dimension and have the position maintained relative to a sensor.
The foregoing objects are basically obtained by providing a lens assembly, comprising: a housing having a lens receiving area, and a first retaining member adjacent the lens receiving area; a lens coupled to the housing within the lens receiving area, the lens having a first lens retaining element, the first retaining element adjustably coupling with the first retaining member; a sensor mounted to the housing and positioned within the housing and behind the lens, wherein the lens is adjustably movable about the sensor between a first position and a second position in a first direction as the first retaining element moves relative to the first retaining member, and the lens is further adjustably movable about the sensor between a third position and a fourth position in a second direction, which is transverse to the first direction, as the second retaining element moves relative to the second retaining member.
The objects are flirter obtained by providing a method of adjusting a lens comprising the steps of providing a housing having a lens receiving area, and a first retaining member adjacent the lens receiving area; providing a lens coupled to the housing within the lens receiving area, the lens having a first lens retaining element, the first retaining element adjustably coupling with the first retaining member; providing a sensor mounted to the housing and positioned within the housing and behind the lens, moving the lens about the sensor between a first fixed position and a second fixed position in a first direction.
The objects are further obtained by providing a lens assembly, comprising: a housing having an outer surface, a lens receiving area, and a first retaining member adjacent the lens receiving area; a lens coupled to the housing within the lens receiving area, the lens having a first lens retaining element, the first retaining element adjustably coupling with the first retaining member; a sensor mounted to the housing and positioned within the housing and behind the lens, wherein the lens is adjustably movable about the sensor between a first position and a second position in a first direction as the first retaining element moves relative to the first retaining member, and the first retaining member extending from the outer surface of the housing to direct contact with the lens, and the first retaining member being movable between an original position and a final position while engaging the lens to move the lens between the first and second positions.
The objects are still further obtained by providing a method of adjusting a lens, comprising the steps of: providing a housing having an outer surface, a lens receiving area, and a first retaining member adjacent the lens receiving area; providing a lens coupled to the housing within the lens receiving area, the lens having a first lens retaining element, the first retaining element adjustably coupling with the first retaining member; providing a sensor mounted to the housing and positioned within the housing and behind the lens; moving the lens about the sensor between a first position and a second position in a first direction as the first retaining element moves relative to the first retaining member by moving the first retaining member.
Other advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.